A U.S. Food and Drug Administration advisory panel on Wednesday unanimously recommended the agency approve a “biosimilar” version of Amgen Inc.’s cancer drug Neupogen.

Neupogen had global sales of $5.8 million in 2013 but its U.S. patent expired in December. The drug stimulates production of white blood cells in bone marrow and is given to patients undergoing radiation or chemotherapy, which depletes white cell counts.

The copycat drug from Novartis AG, called Zarxio, would be the first biosimilar drug to receive FDA approval. Biosimilars are medicines that copy proprietary biotech drugs when patent protection expires. Because small differences in environment or manufacturing processes may alter the final product, the drugs are called similar – but not identical – to the original drug.

The panel recommended Zarxio be approved for the same five conditions that Neupogen treats. The FDA will give final approval for Zarxio in March, but the agency nearly always follows the recommendation of its expert panels.

Amgen shares closed up $5.34 or 3.5 percent to $158.24 on the Nasdaq.